Francesco D'Angelo

Francesco D'Angelo is an optical specialist associated with Edmund Optics, whose own laser-optics staff directory identifies him as a Senior Solutions Engineer.^[ref] He is the named author of the technical note Propagation of a Gaussian Beam Through a Thin Lens by Francesco D'Angelo, which explains Gaussian beam propagation and transformation by a thin lens.

The note relates beam waist, beam divergence and Rayleigh range, then uses the complex beam parameter to calculate how a thin lens changes the beam. This connects an optical component specification to the actual position and size of a focused beam, instead of treating every incident beam as a perfectly parallel bundle of rays.^[ref]

An illustrative consequence of the note's ideal Gaussian beam relation $w_0\theta =\lambda /\pi$ is easy to check. At a fixed wavelength $\lambda =1\mu \mathrm{m}$, a beam waist radius of $0.5\mathrm{mm}$ gives a far-field beam divergence half-angle of approximately $0.637\mathrm{mrad}$. Halving the beam waist radius doubles that half-angle. Focusing to a smaller spot and obtaining lower beam divergence cannot be chosen independently within this model.^[ref]

The employer's laser-optics staff directory includes a labeled portrait.